Apply dependency-management plugin consistently to the docs

[jonatan-ivanov]

@izeye spotted that we have inconsistencies in the Boot docs and the build.gradle file generated by initializr seems inconsistent too.

The Boot documentation recommends adding the dependency-management plugin this way:

plugins {
	id 'java'
	id 'org.springframework.boot' version '3.1.0'
}

apply plugin: 'io.spring.dependency-management'

Initializr does this:

plugins {
  id 'java'
  id 'org.springframework.boot' version '3.1.0'
  id 'io.spring.dependency-management' version '1.1.0'
}

Also, it was called out in the linked discussion that the former is probably better since the org.springframework.boot plugin can manage the version of io.spring.dependency-management.

[wilkinsona]

Also, it was called out in the linked discussion that the former is probably better since the org.springframework.boot plugin can manage the version of io.spring.dependency-management.

If you only use the plugins DSL, the version of org.springframework.boot's transitive dependency on io.spring.dependency-management will be considered as part of Gradle's usual version conflict resolution. The highest version will win.

If you use apply plugin: 'io.spring.dependency-management' the specific version that org.springframework.boot depends upon will be used.